Kinetics of Growth of Gas-Saturated (Embrittled) Layers on Titanium during Vacuum Annealing

摘要

The influence of the parameters of the vacuum annealing mode on the thickness of the embrittled layers, formed on the surface of titanium as a result of its interaction with the residual gases of the vacuumed space, is studied. The thickness and structure of the layers were determined on samples made of VT6 alloy obtained from sheet metal with a thickness of 3 mm. Annealing of samples in the temperature range of 500-750 °C was performed with air dilution from 10 to 3·10~(-2) PA. The dimensions of the embrittled layers were determined by measuring the zone of brittle crack propagation in the fracture of the samples, and measuring the distance between the surface cracks in the embrittled layers, formed during bending deformation. To quantify the effect of vacuum annealing modes of sheet titanium alloy VT6 on the depth of the embrittled part of the formed oxide layer, it is proposed to use a parabolic relationship, characterized by the degree of growth and the constant of the embrittled layer. By processing experimental data, the effect of annealing time, temperature, and air dilution on the growth kinetics of the embrittled layers was established. Based on the obtained kinetic regularities of the growth of the embrittled layers, nomograms are constructed, to determine the size of the embrittled layer formed at the heating stage at different speeds up to the specified annealing temperature.